1. Field of the Invention
The present invention relates to an ink-jet recording method, etc. in which images are formed by ejecting a recording liquid such as ink onto a recording medium while scanning recording means.
In particular, the present invention relates to an ink-jet recording method, etc. in which a deterioration in image quality is prevented by reciprocal scanning.
2. Description of the Related Art
Conventionally, an ink-jet recording method for performing recording on various recording mediums is capable of high-density and high-speed recording operation, so that it is applied to a printer, a portable printer or the like as an output medium of various apparatuses, which have become commercial.
Here, the individual recording apparatuses assume constructions in correspondence with the functions, forms of use, etc. peculiar to them.
Generally speaking, an ink-jet recording apparatus is provided with a carriage on which a recording means (recording head) and an ink tank are mounted, a feeding means for feeding the recording medium, and a control means for controlling these components. And, the recording head, which ejects ink droplets from a plurality of ejection holes, caused to perform serial scanning in a direction which crosses, for example, at right angles, the direction in which the recording medium is fed (sub scanning direction), and, when no recording is being performed, the recording medium is intermittently fed by an amount equal to the recording width.
This recording method, in which ink is ejected onto the recording paper in correspondence with a recording signal, is widely used as a recording system which is of low running cost and quiet. Recently, a number of products which use a plurality of inks and applied to color recording apparatuses have been put into practical use.
When the ink-jet recording method is applied to a color recording apparatus, the construction of the recording head can be roughly classified into two types.
One is a recording head in which, as shown in FIG. 14, a number of nozzles ejecting ink are arranged in a line in the sub scanning direction. In the construction shown in FIG. 1A, nozzles 100y, 100m, 100c and 100k for ejecting yellow, magenta, cyan and black inks are arranged in a line in the sub scanning direction such that the colors do not overlap each other. In the construction shown in FIG. 1B, a nozzle 101k for ejecting black ink is separate from nozzles 101y, 101m and 101c for ejecting color inks. As is apparent from FIG. 14, regarding yellow, magenta and cyan, when so-called secondary colors, blue, red and green are formed to form images of different colors at different positions on the recording medium, the order in which the colors are superimposed on each other is fixed independently of the scanning direction of the recording head. For example, when forming a blue image, recording is first performed in cyan and then recording in magenta is performed thereon. Thus, when the recording head 100 or the recording head 101 is used, no inconsistencies in color are generated if recording is performed through forward scanning and backward scanning.
However, if the number of nozzles for different colors is increased to achieve an increase in speed, the length of the recording head is increased, resulting in an increase in size, or the method of holding the recording medium in the recording portion is complicated, resulting in an increase in the cost of the recording head or the apparatus.
In the second type of construction, recording heads 102k, 102c, 102m and 102y for ejecting black ink, cyan ink, magenta ink and yellow ink are arranged in the main scanning direction as shown, for example, in FIG. 2. When this recording head 102 is used, the inks of all colors are ejected in correspondence with image data by one scanning.
Here, when, to achieve an increase in speed, an image is formed by alternately repeating main scanning (in the direction A) and sub scanning (in the direction B), when so-called secondary colors, for example, blue, red and green, are formed, the order in which colors are superimposed on each other differs between the main scanning (in the direction A) and sub scanning (in the direction B), with the result that the color taste (hue) differs between the main and sub scanning, so that inconsistencies in color are generated, resulting in a substantial deterioration in image quality.
In the following, the problems involved when the recording order differs will be specifically described.
To execute full color recording in an ink-jet recording apparatus forming images using inks of four colors, ink droplets of the inks of the four colors are caused to reach the recording medium in appropriate balance, and other colors are generated through mixing. When recording a green (G) image, recording is performed by mixing C and Y. That is, C and Y dots are placed at the same pixel.
FIG. 3 shows the condition of an ink droplet caused to reach ordinary paper by using the head of FIG. 2. FIG. 3A is a sectional view of an ordinary paper sheet at the time of forward recording (C Y), and FIG. 3B is a sectional view thereof at the time of backward recording (Y C). In FIG. 3A, recording is first performed in C to cover the surface, and Y, in which recording is performed afterwards, goes deeper than C.
Conversely, in FIG. 3B, recording is first performed in Y to cover the surface, and C, in which recording is performed afterwards, goes deeper than Y. When seen on the surface, the recording of FIG. 3A appears to be of a green that is rather cyanish, and the recording of FIG. 3B appears to be of a green that is rather yellowish. Thus, if the colors mixed are the same C and Y, the hue completely differs between the forward and backward recordings. As a result, color inconsistency is alternately generated at each line feed.
As described above, the construction of the ink-jet recording head applied to the color recording apparatus is of two types, of the type (the latter) in which the nozzles of the different colors are arranged in the scanning direction is suitable for achieving an increase in the speed of the apparatus. However, this type involves a problem that inconsistency in color is generated due to the difference in the order in which the colors are superimposed on each other between the forward scanning and the backward scanning of the recording head.
To prevent the above-described inconsistency in color in reciprocation, Japanese Unexamined Patent Application Publication No. 5-278232 proposes a system in which, to complete the recording of a predetermined region by a plurality of main scanning operations, thinning-out images are sequentially recorded while sequentially selecting a plurality of thinning-out arrangements in a complementary relationship. Disclosed is a method in which the thinning-out arrangement selected in the same scanning differs between the colors. In this method, however, a so-called multi-pulse recording is performed in which recording is completed by a plurality of main scanning operations, so that the requisite time for complete the recording is rather long.
Further, in Japanese Unexamined Patent Application Publication No. 6-106736, when performing recording while reciprocating the recording head of different colors having a recording density higher than the input image data in the arrangement direction, the recording image is composed of a plurality of pixels (2xc3x972) with respect to one pixel of the input image data, so that, when recording a mixed color image, inks of two or more colors are not superimposed on the 2xc3x972 pixels. However, in this method, the recording resolution is lower than the resolution the recording head originally possesses.
To solve the above problem, Japanese Examined Patent Application Publication No. 3-54508 discloses a method in which the color processing method differs between the forward scanning and the backward scanning of the recording head. However, in this method, two kinds of color processing tables for the forward scanning and backward scanning are necessary.
Further, when performing recording with an ordinary printer, the color processing is conducted in a printer driver on the host computer, the image data after color processing is transferred to the printer main body, and the printer main body processes the received image data in conformity with the recording head. However, when performing the color processing in the printer driver, it is necessary to perform the color processing in a condition in which the way the processed image data is recorded on the main body side is previously known. That is, it is necessary for the host computer to know whether the recording is performed by the forward scanning or the backward scanning of the recording head. This very much complicates the system including the printer driver and the printer main body.
Further, the color reproduction regions (hues) of the forward scanning and the backward scanning are usually deviated, so that, when the color processing is changed so that a common color reproduction region is adopted for the forward scanning and the backward scanning, the color reproduction region is reduced, so that there is a fear of the image quality being deteriorated.
The present invention has been made in view of the above problems. It is an object of the present invention to achieve a high printing quality and a reduction in recording time as much as possible while preventing a deterioration in quality due to color inconsistency due to reciprocation, thereby achieving a recording shorter than any multi-pass recording or one-pass one-direction recording, making it as close as possible to one-pass reciprocating recording.
Further, the present invention copes with the color inconsistency due to the difference in ejection color order due to the reciprocative recording using a recording head in which nozzles of different colors are arranged in the scanning direction as described above and a reduction in recording speed due to the fact that only one-direction recording is performed; it is an object of the present invention to provide an ink-jet recording method, a recording apparatus, etc. in which, even in the case of a color recording apparatus in which the ink ejection order differs between the forward scanning and backward scanning, it is possible to achieve an improvement in recording speed while reducing color inconsistency.
To achieve the above object, there is provided, in accordance with the present invention, an ink-jet recording method in which scanning is performed with a recording means having a plurality of recording element groups in correspondence with inks of different hues relatively in a direction crossing the direction in which the recording medium is fed to perform recording, wherein the scanning direction is determined according to the duty of the image data in the scanning for recording, the recording being performed by performing scanning in the determined scanning direction.
Alternatively, there is provided an ink-jet recording apparatus in which scanning is performed with a recording means having a plurality of recording element groups in correspondence with inks of different hues relatively in a direction crossing the direction in which the recording medium is fed to perform recording, comprising a means for determining the scanning direction according to the duty of the image data in the scanning for recording, and a means for performing recording by performing scanning in the determined scanning direction.
Alternatively, there is provided an ink-jet recording method which comprises a step for performing scanning a recording means provided with a plurality of recording element groups in correspondence with inks of different hues in a direction in which scanning is performed relatively with respect to the recording medium to perform recording on the recording medium, and a step for feeding the recording medium in a direction crossing the scanning direction, and in which recording is performed according to the scanning direction determined according to the recording duty obtained from a predetermined region of image data corresponding to the scanning region, wherein the determination of the scanning direction is effected according to the duties of at least two regions, i.e., a region positioned in the vicinity of a border portion of the scanning region as the predetermined region, and a region different from this.
Alternatively, there is provided an ink-jet recording apparatus in which a recording means provided with a plurality of recording element groups in correspondence with inks of different hues in a direction in which scanning is performed relatively with respect to the recording medium is scanned to perform recording on the recording medium, and in which recording is performed according to the scanning direction determined according to the recording duty obtained from a predetermined region of image data corresponding to the scanning region, the apparatus comprising a means for feeding the recording medium by a predetermined amount in a direction crossing the scanning direction, and a calculating means for determining the scanning direction according to the duties of at least two regions, i.e., a region positioned in the vicinity of a border portion of the scanning region as the predetermined region, and a region different from this.
Alternatively, there is provided a recording apparatus comprising a control device in which a recording means provided with a plurality of recording element groups in correspondence with inks of different hues in a direction in which scanning is performed relatively with respect to the recording medium is scanned to perform recording on the recording medium, and in which recording is performed according to the scanning direction determined according to the recording duty obtained from a predetermined region of image data corresponding to the scanning region, the apparatus comprising a calculating means for determining the scanning direction according to the duties of at least two regions, i.e., a region positioned in the vicinity of a border portion of the scanning region as the predetermined region, and a transmission means for transmitting information regarding the determined scanning direction to the recording apparatus side.
Alternatively, there is provided a storage medium storing a control command in which a recording means provided with a plurality of recording element groups in correspondence with inks of different hues in a direction in which scanning is performed relatively with respect to the recording medium is scanned to perform recording on the recording medium, and in which recording is performed according to the scanning direction determined according to the recording duty obtained from a predetermined region of image data corresponding to the scanning region, the storage medium comprising a control command for calculating according to the duties of at least two regions, i.e., a region positioned in the vicinity of a border portion of the scanning region as the predetermined region, and a control command for determining the scanning direction according to the recording duties of these plurality of regions.
Alternatively, there is provided a network apparatus storing a control command in which a recording means provided with a plurality of recording element groups in correspondence with inks of different hues in a direction in which scanning is performed relatively with respect to the recording medium is scanned to perform recording on the recording medium, and in which recording is performed according to the scanning direction determined according to the recording duty obtained from a predetermined region of image data corresponding to the scanning region, the network apparatus comprising a control command for calculating according to the duties of at least two regions, i.e., a region positioned in the vicinity of a border portion of the scanning region as the predetermined region, and a control command for determining the scanning direction according to the recording duties of these plurality of regions.
Further objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.